Automatic stack damper



June 7, 1932. V J. E LUDWIG 1,862,272

AUTOMAT IC STACK DAMPER Filed Aug. 51, 1928 2 Sheets-Sheet 1 7; jmoentoz Jajuz 1 Ludwig arbor/"m June 7, 1932. J. E. LUDWIG AUTOMATICSTACK DANH ER 2 Sheets-Sheet Filed Aug. 51. 1928 wucnfor JnhzzELzrdzzrigPatented June 7, 1932 STAS JOHN E. LUDWIG, OF DETROIT, MICHIGAN,ASSIG-NOR TO NEWCOMB-DAVID G0. INC, OF

DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN AUTOIEATIC STACK DAMPERApplication filed August 31, 1928.

The present invention pertains to a novel automatic damper forcontrolling air currents through Ventilating stacks, of the typeemploying an induced draft.

The primary object of the present invention is to eliminate unnecessaryexpenses by avoiding loss of heat over night from factories and similarlarge buildings, through the ventilator pipes. The loss ordinarily isconsiderably large, due mainly to the fact that the heat escapes throughthe ventilating pipes after the work of the factory has been suspended,and there being no further necessity for ventilation as the machineryhas ceased to operate. Ordinarily the stack pipe remains open afteroperations in the factory have been suspended. This admits cold draughtsand the elements toenter the rooms and also allows warm air to escape.

A further object is to devise an automatic damper having controllingmeans governed by the siphon means which causes the ventilatingcurrents. The siphon means consists of a nozzle directing a flow of airupwardly in the stack pipe, the damper operating mechanism beingattached to the nozzle and caused to move by the flow of air through thenozzle. The dampers are so constructed that immediately the air flow isdiscontinued the damper automatically closes and seals the pipe,preventing all circulation of air or draughts through the stack pipe.

With these and other objects in view, the manner in which I attain theseobjects is fully disclosed in the following description, with referenceto the accompanying drawings, in which Fig. 1 is a plan View of thedamper mechanism taken on a cross section through the stack pipe;

Fig. 2 is a cross sectional view on the line 22 of Fig. 1

Fig. 3 is a cross sectional view on the line 3-3 of Fig. 2;

Fig. 4 is a side elevation. of a section of the stack pipe partly brokenaway. showing a slightly modified embodiment of my invention; and

Fig. 5 is a cross sectional view on the line 55 of Fig. 4.

Serial No. 303,135.

Similar characters of reference are employed to designate thecorresponding parts throughout the several views.

In reference to the embodiment disclosed Figs. 2 and 3 of the drawings,being formed.

with the tapered portion 3. The tapered portion?) accommodates brackets4 which are formed with upwardly extending ears, providing suitablemeans for pivoting shutter members 5. The shutter members are piv otallyconnected by the cross members 6, the cross members causing the severalshutter members to move in unison.

' A pipe 7 is provided at its outer end with a suitable air blowingdevice not shown). the inner end, extending through the wall of the pipe2, is formed with a nozzle 8. which directs the air at a great velocityupwardly in the stack pipe. The nozzle 8 is formed with a flange 9, anda cover plate 10 is hinged, as at 11, to the flange 9. The outward endsof the hinge 11 and connected to the cover plate and movable therewith,are provided the arms 12. these arms 12 being connected. at their outerends. to the cross members 6 on the shutter members. by means offlexible cords or chains 12.

The cover plate 10 is further provided with an angularly extending arm14 to which adiustably secured is the weight 15, the weight beingmovable along the arm 14 and having a set-screw 15 by which it may besecured at any point on the arm 14. The weight 15 is thereby capable ofcounterbalancing the cover plate 10 and the arms 12. upon the hinge 11.so that a comparatively small air pressure through the nozzle 8 willmove the cover plate 10 outwardly and upwardly on the hinge 11.

Adjustment of the weight or any of the parts needing replacements may beconveniently made by access through the door 16 in the section 2 of thestack pipe.

In operation. of the embodiment described, the air being forced throughthe nozzle 8. forces the cover plate 10 upwardly upon the hinge 11, andat the same time correspond ingly raising the arms 12. The arms 12,being in connection with the shutters 5, by means of the flexibleconnection 12 and the cross members 6, upon the movement described causethe shutters 5 to assume the erect, or open position, indicated inFigures 1, 2 and 3 in the drawings.

Immediately, in event of the air flow through the nozzle 8 beingdiscontinued, the cover plate 10 lowers until in a flat position uponthe flange 9 on the nozzle 8. The arms 12 are correspondingly loweredwith the cover plate 10 and thereby allow the shutters to settle to theposition indicated by the broken lines in Figure 3.

In the embodiment disclosed in Figures 4 and 5 is shown a section 20 ofa. ventilator stack having a pipe 21 extending through the wall of thestack. The pipe 21 is turned upwardly within the stack and is pro sidedwith a nozzle 22. A cover plate 23 is hinged over the nozzle 22 by meansof the integral rod 24 being supported in hearings in the stack pipe 20,the cover plate 23 being counter-balanced by the adjustable weight 25upon the arm 26.

A butterfly damper 27 is pivoted within the stack section 20 upon a rod28 which e);- tends outwardly of the stack 20 and is provided with across arm 29 connected at its center to the rod 28 so as to turntherewith. Connected to one end of the arm 29 is a link 30 having apivotal connection at its upper end to a lever arm 31 attached to therod 24, the other end of the arm being provided with the weight 29.

In operation the air rushing through the nozzle causes the cover plate23 to rise upwardly, turning the rod 2d and ra sing the lever arm 31.The link connection 30 in turn causes the arm 29 to turn the rod 28 andmove the butterfly damper to an open position. When the air flow isdiscontinued through the nozzle the cover plate returns to a positionflat upon the nozzle and butterfly valve assumesthe closed position. Theweight of the link connection being sufficient to return the parts ofthis position, the parts being counterbalanced by the weights 25 and 29so as to require a comparatively small pressure to operate.

The air, in being ejected from the nozzle in the ventilator stack at ahigh velocity, due to a loss of pressure caused by the reduction incross sectional area of the pipe 7 or 21, tends to create a partialvacuum below the nozzle. The air is drawn from the room to fill thispartial vacuum and is passed onwardly up the stack to the atmosphere.

The dampers are caused to open or close by the means creating thesuction, opening or closing in response to the said means, The passageis thereby automatically closed immediately there is no need for aircirculation and thus eliminating all waste of heat and neeaare sealingthe connected room from the elements.

Although specific embodiments of my invention have been illustrated anddescribed, it will be understood that various alterations, in thedetails of construction, may be made without departing from the spiritof the invention, as indicated by the scope of the appended claims.

lVhat I claim is:

1. The combination with a ventilator stack of a plurality or pivotedshutters adapted to prevent circulation of air through said stack whensaid shutters lie in a horizontal position, a nozzle adapted to create aflow of air "1 said stack above said shutters, a pivoted plate adaptedto lie flat on the opening in said nozzle whereby a flow of air throughsaid nozzle causes said plate to assume a vertical position, andconnecting means between said shutter and plate for causing saidshutters to assume a vertical position when said plate is moved to avertical position by the flow of air through said nozzle.

2. In combination, a ventilator staclr, an air conducting conduit havingone end ere tended within the ventilator stack for creat ing a flow ofair through the stack, a normally closed damper in the stack below theconduit, a plate pivotally mounted on the discharge end of the conduitand normally urged to a position to overlie such discharge end and movedto a position. at right angles to its normal position during the passageof air through the conduit, and an operative connection between theplate and damper to open and close the latter incident to the movementof the plate.

3. In combination, a ventilator stack having the discharge end of apressure conducting conduit extended therein for creating a flow of airthrough the stack, a plate pivoted on the discharge end and normal yurged to a position to overlie the discharge end and raised to aperpendicu ar position by the passage of pressure through the conduit,an arm attached to the plate, a damper in the stack, and an operativeconnection between the arm and damper whereby to control the latterincident to the movement of the plate on its axis.

4. In a control for ventilator stacks, a damper for controllingventilation through the staclr, a plate adapted to be pivotally supported on the discharge end of a pneumatic ejector arranged to dischargeabove the damper, an arm attached to one side of the plate, and anoperative connection between the arm and damper whereby the latter willbe controlled incident to the movement 01 the plate by the pneumaticpressure discharged against the plate from the pneumatic ejector.

In testimony whereoi. I aflix my signature.

JOHN E. L'Unwre.

